Fort Madison, IA 52627 Frost Dates
52627, near Fort Madison, IA: the frost window
Typically, the last spring freeze lands around 04/12, roughly 227 days out. Fall's first freeze usually shows up around 10/25, roughly 194 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Fort Madison in Zone 6a (-10 to -5°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
Fort Madison's growing season runs out in roughly 8 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 04/12 isn't a guarantee
04/12 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/01 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/26 and only about 1 year in 10 sees frost after that.
Fort Madison against the rest of the dataset
About 194 days separate Fort Madison's last and first frost, putting it 19,463 of 40,283 ZIP codes nationally. Within IA, it ranks 3 of 1,042.
Learn more
Two guides worth reading on 52627: zone vs. frost date, on why Zone 6a and Fort Madison's frost date answer different questions, and the frost range, on how to read the range around Fort Madison's dates instead of trusting one.